Electric drill



i (No Model.)

G. BUCHANAN. ELECTRIC DRILL.

No. 438,837. Patented Oct. 21, 1890.

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UNITED STATES PATENT OFFICE.

GORDON BUCHANAN, OF QHICAGO, ILLINOIS.

ELECTRIC DRILL.

SPECIFICATION forming part of Letters Patent No. 438,837, dated October21, 1890.

Application filed March 31, 1890.

To aZZ whom, it may concern.-

Be it known that I, GORDON BUCHANAN, a citizen of the United States,residing at Ohicago, Illinois, have invented a new and usefulImprovement in Electric Drills, of which the following isaspecification.

The object of this invention is to provide a simple and efficient drilloperated by means of electricity and adapted for use in coalmines andother places where a drill may be employed; and the invention consistsin the features and details of construction hereinafter described andclaimed.

The drawing represents a central sectional view of my improved drill,the wire of the magnets being merely shown in a general way.

A and B are two electro-magnets; A and 3, the spools thereof; A B, thewires with which the same are wound.

O is a ring connecting the spools A and B; D, an armature; D, thedrill-stock attached thereto; E, a circuit-closer; F F, contactrings;f,the binding-post connecting with the contact-ring F, and to which thewire 13 is attached. f is a similar binding-post connecting with thecontact-ring F and the wire A G, a contact-ring inelosing thecircuitcloser E; g, a binding-post connecting with such plate and withthe wire leading from one pole of the dynamo; H, a binding-postconnected with the other pole thereof, and I I suitable insulatingmaterial.

The spools A and B are made of soft iron, and preferably in the formshown in the draw in g. They are preferably connected, as shown, bymeans of a ring O, one of the spools screwing into each end of suchring. Inside of the case thus formed is placed the movablecircuit-closer E. This consists of a ring of metal of the form shown,and preferably made in two pieces 6 e, screwing together to facilitatethe assembling of the parts. The circuitcloser is kept from contactingwith the ring O by means of suitable insulating material I.

The contact-rings F F are made of any suitable conducting material andheld out of corn tact with the ends of the spools A B by means ofinsulating material interposed between them. Surrounding thecircuit-closer, in contact therewith, and preferably embedded ininsulating material, is a ring G of suitable conducting material.Binding-posts f, f and Serial No. 345,941. (No model.)

9 are provided, connecting with these cont-aetplates. The purpose ofmaking these contact-plates F, F, and G in the shape of rings is inorder to insure more uniform working of the parts, since these ringswill be in con tact with the circuit-closer E throughout its wholecircumference, instead of at a single point, thus insuring contactbetween circuitcloser and ring, even though the parts of the device wearso as to cause the circuit-closer to move unevenly.

The armature D consists of a circular disk of soft iron of any suitabledimensions, adapted to contact, as shown, with the flanges on thecircuit-closer E. This dish is secured by screw-threads or otherwise tothe drill-stock D, which passes, as shown, through each of the spools,which are cored out to afford a bearing for it. A layer of insulatingmaterial I is placed between this drill-stock and the inner surface ofthe spools. In one end of this stock is secured the drill J, of anysuitable form, and which, being well known, need not be further shown ordescribed.

The wire A is connected with the bindingpost f, then passes to and iswound around the spool A in the well-known manner, and then passes tothe binding-post II. In the drawing I have merely shown four or fivecoils of wire wound around the spool; but it will of course beunderstood that the spool is to be wound in the ordinary manner. Thewire B is connected with the binding-postf, then passes to and is woundaround the spool B, and thence to binding-post H, which, as abovestated, is connected with one of the poles of the dynamo. From thebinding-post II which is connected with the other pole, a wire runs tothe post 1.

The parts may be put together in the following manner: The spool 13 isscrewed into the ring O, and the ring F, together with its insulatingmaterial, is secured in a channel, preferably formed in the end of thespool, and the contact-ring G, with its insulating material securedinside of the ring 0. The part 6' is then screwed out of thecircuit-closer and the part 6 passed over the armature. Such part c isscrewed back again, after which the circuit-closer and armature may beplaced inside of the ring O. The drill-stock may then be secured to thearmature, or this may be done before the armature is put inside of thering 0. The ring F, with its insulating material, may then be attachedto the spool A, and the latter passed down over the drill-stock andscrewed into the ring 0. The wires are then connected as abovedescribed, and the device is then ready for operation, the mode of whichis as follows:

The parts being in the position shown in the drawings, the current fromone pole of the dynamo flows in through post g, passing through the ringG, circuit-closer E, ring F, and binding-post f into the wire B,magnetizing the spool B. The spool then attracts the armature D. As thismoves toward the right it strikes during the latter part of its strokeagainst the flange on the part e of the circuit-closer and moves thelatter toward the right, breaking the contact with the plate F andbringing it into contact with the plate F. The instant this contact ismade the current flows through the post g, plate G, circuit-closer E,plate F, binding-post f, and wire A, magnetizing the spool or core A.This in turn attracts the armature, breaks the contact with the ring F,and renews it with the plate F, when the core B becomes magnetized andacts as before. In this way a constant and rapid motion is given to thedrill-stock. Each time the armature moves toward the left it carries thedrill with it, striking the blow, and then moves toward the'right to getready for a new blow. The drill may be used in any position and in anyplace desired.

From the form of the circuit-closer it will be evident that the armaturewill not move it to break contact until the latter part of its stroke.This leaves the circuit-closerin connection with one magnet until thearmature approaches nearly to the other magnet, when the circuit-closerwill be moved to break such connection and make connection with theother magnet.

I do not of course desire to limit myself to the exact forms hereinshownas, for instance, the contact-plates F, F, and G need not be madein the form of rings, but may be simple plates adapted to contact withthe circuit- 1. In an electric drill, the combination of twoelectro-magnets, connected substantially as shown and provided withhollow cores or spools, a movable armature placed between such magnets,a drill-stock attached to such armature and passing through the hollowcores or spools, and a circuit-closer adapted to be moved by thearmature to close the circuit with each of said magnets in alternation,substantially as described.

2. In an electric drill, the combination of two electro-magnets A and B,having hollow cores and connected by means of a ring 0, an armature D, adrill-stock D, attached thereto, a circuit-closer E, surrounding sucharmature, contact-plates F F, connected with the wire of the magnets Band A, respectively,

and contact-plate G, connected with the dynamo, all combined andoperating substantially as described.

3. In an electric drill, the circuit-closer E, made in two flangedportions e e, screwing together, as shown, substantially as described.

4. In an electric drill, the combination of an electro-magnet A andcontact-plate F, magnet B and plate F, plate F being connected withmagnet B and plate F with magnet A, an armature placed between andactuated by such magnets, and a circuit-closer operated by means of sucharmature, whereby as the armature is attracted by one magnet it movesthe circuit-closer to break connection therewith and make connectionwith the other magnet, substantially as described.

GORDON BUCHANAN.

Witnesses:

GEORGE S. PAYsoN, SAMUEL E. HIBBEN.

